This invention relates to shut down protection apparatus used in conjunction with an electronic fuel-injection control circuit for a water-cooled internal-combustion engine of the type described in my copending U.S. patent application Ser. No. 120,467 filed Feb. 11, 1980 and my U.S. Pat. No. 4,280,465 issued July 28, 1981. Reference is made to said application and to said United States Patent for greater descriptive detail of a fuel injection engine, to which the present invention is illustratively applicable. Although the internal combustion engines discussed in said application Ser. No. 120,467 and said U.S. Pat. No. 4,280,465 are not specifically shown as being water cooled it is understood that the manner in which said marine outboard engines are water cooled is well known and thus the specific manner of cooling will not be discussed herein.
In fuel injection control circuits of the character indicated both the ignition circuit and the fuel supply are normally turned off at engine shut down. With water-cooled engines the engine block will cool down faster than the pistons, resulting in uneven cooling between the pistons and the engine block. Such uneven cooling can cause damage when the engine is shut down and is especially detrimental when the engine is turned off while running at high speed.